1. Field of the Invention
The present invention relates to vibration barrel grinding devices and more particularly to a vibration barrel grinding device adapted to grind light work articles.
2. Description of the Prior Art
In a conventional toroidal-shaped vibration barrel grinding device, as shown in FIG. 1, a mass contained in the toroidal-shaped barrel tub 1 resonates with a forcible rotary vibration given to the arcuate bottom wall 1a of the barrel tub 1 so as to be forcibly made to rise as indicated by the arrow "a" toward the outer peripheral wall 1b from the arcuate bottom wall 1a and the thus elevated mass flows as indicated by the arrow "b" in the drawing toward the inner peripheral wall 1c of the barrel tube 1 and rotates while flowing to the arcuate bottom wall 1a of the barrel tube 1.
Such rotary motion of the mass in the barrel tub is given by rotating an upper weight 3a and bottom weight 3b fitted to both ends of a motor 2 so as to strongly vibrate the barrel tub 1 mounted on springs 5 on a mount 4. Therefore, the strong vibration given to the barrel tub 1 will be transmitted to the mass within the barrel tub and will forcibly rotate the mass so as to generate a mutual motion having a mutual contact pressure between a grinding material and a work article in the mass to grind the work. If the respective weights 3a and 3b fixed to the shaft of the motor 2 are made to have any advance angle, the mass will rotate and flow in the direction indicated by the arrow c in the barrel tub while spirally rotating as indicated by the solid line arrow in FIG. 2 so as to grind the work. However, there have been defects that, in case the work to be ground is a comparatively light article, is forcibly made to rise as indicated by the arrow a toward the outer peripheral wall 1b of the barrel tub 1 and flows toward the inner peripheral wall 1c, it will float up out of the grinding material, will not submerge into the grinding material, therefore will not be ground and will reduce the grinding efficiency.